This invention relates to the manufacture of magnesium oxychloride cement which is foamed simultaneously with synthetic resin foam-forming ingredients. All of the patents cited in the parent applications and patents have been considered in the preparation of this application. None of those patents shows simultaneous foaming of magnesium oxychloride cement with synthetic resin foam to give a low-density fire-resistant product.
The Harrell, et al U.S. Pat. No. 3,238,155, relates to improving the water resistance of magnesium oxychloride and magnesium oxysulfide cements. There is disclosed in that patent the possibility of using a foaming agent and between 0.05 and 2 weight percent of melamine formaldehyde resin as an agent for improving the water resistance of the cement. While a foam can theoretically be prepared under that patent, it is clearly not the intent of the patent to provide a cement-resin co-foam in which the resin is at least 10% of the weight of the product.